Process for preparing partially vinylated fibrous cotton cellulose and resulting products



United States Patent PROCESS FOR PREPARING PARTIALLY VINYL- ATED FIBROUS COTTON CELLULOSE AND RESULTING PRODUCTS Otto Friedrich Hecht, deceased, late of Easton, Pa., by Richard D. Grifo, legal representative, Samuel A. Glickman, John J. Duncan, and Max E. Chiddix, Easton, Pa.; said Glickman, Duncan, and Chiddex assignors to the United States of America as represented by the Secretary of Agriculture No Drawing. Filed Oct. 6, 1966, Ser. No. 587,368

Int. Cl. D06m 13/02 US. Cl. 8-120 3 Claims ABSTRACT OF THE DISCLOSURE Chemically modified cotton textile fibers etherified with acetylene to a degree of substitution of from 0.08 to 0.74 vinyl ether groups per anhydroglucose unit inclusive, and the process for producing such fibers.

A non-exclusive, irrevocable, royalty-free license in the invention herein described, throughout the world for all purposes of the United States Government, with the power to grant sublicenses for such purposes, is hereby granted to the Government of the United States of America.

This invention relates to novel, chemically modified cotton textile fibers etherified to a degree of substitution over the range of from 0.03 to 0.74 vinyl ether groups per anhydroglucose unit inclusive, which cotton cellulosic textile fibers are composed of cellulose molecules and etherified cellulose molecules arranged in the complex laminated structure characteristic of natural cotton cellulose textile fibers.

The invention further relates to processes for producing the above described chemically modified cotton fibers.

The processes which are one facet of our invention permit of the successful vinylation of cotton sliver, yarn and fabric to a degree of substitution up to and including D.S. 0.74 without destruction of the fibrous form of cotton cellulose characteristic of the natural cotton fiber. We have discovered that fibrous cotton cellulose vinylated according to our methods and to degrees of substitution above about D.S. 0.08 are quite insoluble in cuprammonium hydroxide solution and in bis(ethylenediamine) cupric hydroxide, whereas cotton fibers vinylated to D.S. values of less than about 0.08 are soluble.

Samples of vinylated cotton were checked for solubility at 1% in Schweitzers Reagent (cuprammonium hydroxide containing 1.5% Cu). Samples were agitated for at least 18 hours in the reagent at 25 C. if insoluble.

Samples of the dewaxed cotton sliver were found to be soluble in cuprammonium hydroxide solution as were the vinylated cotton slivers with D.S. values of 0.01 to 0.08. However, cotton sliver which had higher D.S. values were insoluble. Insolubility indicates at least a small amount of crosslinking.

A few samples were also checked in bis(ethylenediamine) cupric hydroxide solution (0.5 M in Cu) prepared according to TAPPI Test T-230 sm-50 (revised). The results were similar to those wherein Schweitzers Reagent was employed.

We have subjected the cotton fibers vinylated according to the processes of our invention to additional chemical tests and to physical tests and the characteristics set forth below are typical.

X-ray diffraction patterns made from vinylated cotton sliver and from vinylated cotton printcloth showed a complete loss of erystallinity at D.S. values above about 0.10.

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This observation is indicative of the fact that there has been, during the vinylation process, good penetration of the crystalline regions by both the catalyst (a strong base) and the vinylation reagent (acetylene).

Estimates of the molecular weights of vinylated cotton samples which were soluble in cuprammonium hydroxide were obtained from the specific viscosities of 1% solutions. The intrinsic viscosities were obtained by using Table 3 of ASTM Test D-1795-62.

A molecular Weight of 43 0,000 was calculated from this data for the untreated cotton slivers. Molecular Weights for the soluble samples of vinylated cotton (D.S. values from 0.01 to 0.08) ranged from 43,000 to 137,000 (Table 30, Appendix). These samples were vinylated with KOH catalyst in N-methyl pyrrolidone as solvent, and with NaOH catalyst in di-n-butyl acetal. None of the samples tested which had been vinylated with KOH catalyst in toluene or dibutyl acetal was soluble in the Schweitzer reagent.

As We stated above, the cotton cellulosic textile fibers vinylated to a D.S. above about 0.07 are characterized by insolubility in reagents that will dissolve unmodified cotton cellulosic fibers and this would indicate that at least some small amount of crosslinking of the cellu lose fibers had occurred as a result of the vinylation. However, Monsanto crease recovery angles (AATCC TTM66-1959T) were determined on vinylated cloth and on controls (unmodified cotton cloth) to see whether any significant amount of crosslinking had occurred as a result of the vinylation.

No improvement in the crease recovery properties of the vinylated cotton cloth over the unmodified control was observed and we conclude therefore that very little crosslinking occurs as a result of our vinylation process.

Attendant with the above test for crosslinking via crease recovery performance we examined the crosslinking propensity of vinylated cotton cloth under the influence of an acid catalyst of the type known to induce polymerization with accompanying cellulose crosslinking.

A sample of cotton printcloth vinylated with acetylene to a D.S. of 0.21 according to the process of our invention was divided into three portions. Each portion was rinsed in water and pressed dry on a flat bed press. One portion was left untreated. A second portion was padded with a 2% weight aqueous solution of a commercially available acid type catalyst (an amine hydrochloride) and the third portion of vinylated cloth was padded with a 2% by weight aqueous solution of magnesium chloride. The catalyst padded portions were allowed to air dry for about five minutes and were then pressed dry on a flat bed press. After drying and pressing the catalyst treated cloth, portions were heat cured at 300 F. for 200 seconds. The heat cured cloth samples were then rinsed with water, squeezed slightly while wet and then dried on a line to permit the observation of smooth drying properties. The cloth sample which had the magnesium chloride catalyst treatment exhibited good smooth drying properties. The cloth sample which received the amine hydrochloride catalyst treatment was only fair with respect to smooth drying properties.

Both catalyst treated cloth samples were rinsed again, pressed dry, conditioned for 2 days at F. and 45% relative humidity, and subsequently subjected to a Monsanto crease recovery angle evaluation. The cloth sample that received the magnesium chloride catalyst treatment showed a dry crease recovery angle of 312 (Warp-I-fill). The cloth sample that received the amine hydrochloride catalyst treatment showed a dry crease recovery angle of 211 (warp-l-fill) and the untreated control showed a dry crease recovery angle of only 167 (warp-l-fill).

The wet recovery angles for the magnesium chloride treated sample, the amine hydrochloride treated sample and the untreated control were 252, 234 and 210 (warp+fill) respectively.

The vinylation of cotton cellulosic fibers thus constitutes still another available route to a wash-wear finish for cotton textile fabrics.

In general the process of our invention which employs acetylene consists of soaking the cotton cellulosic fibers thoroughly with an aqueous solution of a strong base, removing water from the soaked fibers until the water content is about weight percent based on the original weight of the cotton fibers, then vinylating the fibers in an acetylene solvent with acetylene gas at temperatures of about 120 and pressures of about 120 pounds per square inch.

Although we prefer to vinylate via the acetylene method outlined above, we examined the reaction of cotton with ethylene dibromide as a means of introducing vinyl ether groups at least for the lower degrees of sub stitution. The following procedure for cotton sliver is typical.

A sample of dewaxed cotton sliver was impregnated with 300 mole percent of aqueous sodium hydroxide based on moles of anhydroglucose unit, and subsequently dried down to contain 200 weight percent of water based on the original weight of the cotton sliver. The thus impregnated cotton fibers were then treated for a period of 12 hours and at a temperature of 90 C. with 600 mole percent of ethylene dibromide in tetrahydrofuran. The resultant cotton fibers exhibited a D.S. of 0.26 vinyl ether groups per anhydroglucose unit. Similar experiments wherein the amounts of acid binder (sodium hydroxide) and water content were varied yielded products not markedly difierent except of degree of substitution. In all cases, the physical form of the cotton fibers was retained and the loss in weight of the modified cotton approximated that of cotton fibers treated only with sodium hydroxide. In all the products prepared using ethylene dibromide there was a faint yellow discoloration.

We shall now turn once again to our preferred vinylation procedure, namely the process that employs acetylene as the vinylation reagent. The variables include swelling agent, catalyst, catalyst application method, catalyst concentration, soaking time (with KOH catalyst), drying of catalyst impregnated cotton, moisture content, solvent, acetylene pressure, temperature and time.

At the outset it was anticipated that the most difficult problem would be the penetration of the fibers by acetylene under the conditions of low moisture necessary for high rates of vinylation. Because of the successful use of glycol ethers by others in maintaining the cotton in a swollen state, it was felt that swelling agents of this type might be useful in the vinylation reaction. The compounds tried for this purpose were tetraethylene glycol dimethyl ether and triethylene glycol monomethyl ether. The latter can, of course, be vinylated during the vinylation of cotton but would be washed out during the workup procedure.

It was found that no beneficial effect was produced by the glycol ethers. The swelling action of the KOH catalyst together with residual moisture was apparently sufficient for good penetration by the acetylene.

A number of catalysts for the reaction of acetylene with cotton were investigated. These included potassium hydroxide, sodium hydroxide, choline hydroxide zinc acetate and cadmium acetate. Because KOH had proved to be very effective for the vinylation of alcohols in some prior research, it was tried early in our work in the vinylation of cotton.

In general, the use of potassium hydroxide, which is our preferred catalyst, yields uniform penetration of the cotton fibers, high vinylation rates, less degradation of the fibers (as compared with sodium hy rox d 10W color formation, fair retention of fiber strength and reproducible results.

The potassium hydroxide vinylation catalyst was applied to the cotton slivers, yarn, and cloth as an aqueous solution. Uniformity was achieved by squeezing out or draining off excess solution. In the case of the cotton slivers, enough catalyst solution was used to completely saturate the slivers with no excess to drain off.

The effect of catalyst concentration was studied in more detail in the case of potassium hydroxide because of the good vinylation results obtained with this catalyst. The reaction rate was found to be very dependent on catalyst concentration and because of severe degradation of the cotton at higher levels of catalyst concentration, an optimum concentration was found at around 35 wt. percent mole percent) KOH based on the cotton.

The effect of catalyst concentration on vinylation rate is shown in Table I for a series of vinylation of cotton slivers. Each experiment was run for 6 hours at 120 C. using di-n-butyl acetal as the acetylene solvent and suspending medium.

TABLE I.EFFECT OF KOH CATALYST CONCENTRATION 1 Residual water determined by the weight increase of the cotton slivers after impregnation with catalyst solution and drying.

2 Based on weight of washed and dried vinylated cotton slivers as compared to the original weight.

3 Degree of substitution by vinyl ether group as measured by the hydrolysis method.

It is evident from the data in Table I that the higher levels of potassium hydroxide (above 100 mole percent) cause degradation particularly if the cotton is dried to a lower moisture content (i.e., 15% by weight). Leaving more water in the cotton appears to protect the cotton from degradation during the vinylation process, but the extra water greatly decreases the vinylation rate. The time of soaking or ageing the catalyst impregnated cotton fibers before the drying step was found to be an important variable and some data bearing on this particular factor is shown in Tables II and III.

TABLE II.EFFECT OF SOAKING TIME WITH CATALYST S OLUTION Spaking Reaction Product recovtime, hrs. temp, C ery, percent D.S. vlnyl 1 Also 5 hours at 120 C. 3 Dioxane solvent instead of dibutyl acetal.

Good results were obtained at 120 C. when an adequate soaking period was provided. Fair conversions resulted at C. with excellent product recovery. The cotton slivers from the experiments at C. were white or off-white, but in the case of the experiments run at C. the products exhibited a tan coloration.

It was found that a one hour soaking time was sufficient for the cotton broadcloth if it were then squeezed between pressure rollers.

In view of the observation that the time of soaking the cotton slivers with catalyst solution before drying had an important effect on the amount of substitution, additional experiments were conducted to compare soaking times of 16, 1'8, 23, and 48 hours. It appears from a comparison, in which all other reaction conditions were es sentially equal, that the results are equivalent for soaking times from 18 hours to 48 hours. In these experiments,

TABLE IIL-EFFECT OF SOAKING TIME WITH CATALYST SOLUTION [For reaction of 6 hrs. at 120 0.]

Product recov- Soaking time, hrs. ery, percent D.S. vinyl Drying and the effect of residual moisture in the catalyst impregnated fibers are also important variables as they relate to our process of vinylation using acetylene.

We have found that the amount of moisture left in the catalyst impregnated cotton has an inverse effect on the rate of vinylation. The best rates were achieved at water contents of about 20% and below. In a series of vinylations of cotton fibers, a rapid reduction in rate was noted as the Water content was increased to 100% of the weight of the cotton whether the solvent was toluene or dibutyl acetal.

In the early work, the cotton linters or cotton slivers were suspended in tetrahydrofuran which served as an acetylene solvent and carrier as well as the suspending agent. Because of the possibility it would leach water and catalyst from the cotton as well as the hazards of flammability and peroxide formation, other acetylene solvents were evaluated. One of the first tried, di-n-butyl acetal, proved to have excellent properties for this purpose, and was used in much of the subsequent vinylation work. Excellent results were obtained with dibutyl acetal and D.S. vinyl ether values up to 0.55 were obtained with this solvent. Diisobutyl acetal was also checked and found to be equivalent to di-n-butyl acetal.

Because of the art recognizing swelling eifects of cotton in diiferent solvents, vinylation experiments were run in a series of solvents. Very poor results were obtained in pyridine, dimethyl sulfoxide, N-methyl pyrrolidone, dimethyl formamide and dimethyl acetamide. The cotton contained 4% water. By increasing the water content from 4% to 25%, slightly better results were obtained using dimethyl formamide and reasonably good results in N-methyl pyrrolidone (N-methyl-Z-pyrrolidinone).

Dimethyl sulfoxide tends to produce some degraded products with a high vinyl ether content together with nearly unchanged slivers. This may be due to its strong tendency to swell the substituted portions of the fiber thus making further penetration by acetylene much easier in those regions. This tendency is also shown by N-methyl pyrrolidone.

A good vinylation and a product recovery of 89% were obtained in tetraethylene glycol dimethyl ether.

It was found that toluene is a surprisingly good solvent and suspending agent for the vinylation reaction in spite of its poor acetylene dissolving power. It was tried because of its low cost and ready availability. Although vinylation rates are somewhat lower in toluene than in dibutyl acetal, high D.S. values were achieved and the color and product recovery were excellent. D.S. values as high as 0.72 were obtained with toluene in a 24 hour reaction. In the case of cotton cloth, not only was the color much lighter with toluene than with dibutyl acetal, but there was less shrinkage, less puckering of edges and less degradation.

Because of the low solubility of water in toluene (0.034% at 18 C.; 0.2% at 68 there is no tendency to remove water or catalyst from the cloth by solvation.

Acetylene pressure in the range of to 120 p.s.i. has an important elfect on the vinylation rate of simple alcohols, and this was found to be the case in the vinylation of cotton. Table IV below summarizes the results of vinylating cotton in dibutyl acetal at three different acetylene pressures. In each case, the catalyst was 100 mole 6 percent KOH, the temperature 120 C., and the time 6 hours.

TABLE IV.-EFFECT OF AOEIYLENE PRESSURE ON COTTON VINYLATION [Time, 6 hrs.; temp., 120 (3.]

Nitrogen Acetylene pressure, p.s.i. pressure, p.s.i. D.S. vinyl In addition to the expected effect on reaction rate, the vinylation temperature was found to have a considerable effect on the degradation of the cotton. Using the KOH catalyst, good recoveries (92-97%) of vinylated cotton slivers were obtained at vinylation temperatures of and C., but only 70-75% recoveries at C. At C. only 24% of the recovered material was fibrous while 13% was pulpy and 63% was soluble in tetrahydrofuran.

A series of vinylations of cotton was performed at 3, 6, 7 and 12 hours to obtain a better idea of reaction rates. Cotton fibers were impregnated with 100 mole percent KOH, aged for 18 hours at about 25 C., and dried to a moisture content of 12.5%. They were then vinylated in di-butyl acetal at 120 C. for the lengths of time shown in Table V. The D.S. values were obtained by hydrolysis and subsequent titration with hydroxylamine.

TABLE V.REACTION RATE SERIES WITH COTTON SLIVERS Product recov- Reactlon tune, hrs. ery, percent D.S. vinyl TABLE VI.REACTION RATE SERIES WITH COTTON PRINTCLOTH Product recov- Reaetion time, hrs. ery, percent D.S. vinyl EXAMPLE 1 Vinylation of cotton with acetylene To 100 g. of 11.5 weight percent potassium hydroxide (0.207 moles) was added 33 g. (0.204 moles of anhydroglucose unit) of dewaxed, dried, cotton fibers. The cotton used was Acala 4-42 (1962 crop), dewaxed by a 6-hour extraction with ethanol in a Soxhlet extractor. After the extraction for the removal of wax, the cotton was dried to an average content of 1.9% volatiles. This amount of KOH was suflicient to completely wet and thoroughly soak the cotton when a slight pressure was applied to the mass by means of a rubber or glass stopper. The impregnated cotton was allowed to soak for a specified time at room temperature (at about 25 C.) in a tightly closed container. The cotton was then spread out in a glass dish and dried at 36 C. in a heated desiccator at a pressure of 1 to 2 mm. mercury until the desired weight was reached.

In a typical experiment, 3.5 g. of water were removed by evaporation leaving 49.5 g. of catalyst impregnated cotton with a water content of as referred to the original weight of the cotton. The cotton was weighed rapidly, divided into two equal parts, each containing 0.10 g. equivalent of cotton on the anhydroglucose basis, and kept in tightly closed bottles prior to Vinylation.

For each Vinylation experiment, one portion of the cotton (0.10 equiv.) was charged to a clean, dry one-liter autoclave together with 350 g. of the acetylene solvent. The autoclave was closed, pressure tested, and purged three times with 300 p.s.i.g. of a suitable inert gas (nitrogen or propane). After adjusting the starting pressure to 15 p.s.i.g., the autoclave was-stirred at 400 rpm. and heated to reaction temperature. The pressure was then adjusted to the specified level with the inert gas (about 100 p.s.i.g.), and brought to 200 p.s.i.g. with acetylene contained in a small gas cylinder. The reaction was continued for the specified time with the acetylene valve open at 200 p.s.i.g.

At the end of the reaction period, the autoclave was cooled and discharged. The cotton was washed with tetrahydrofuran to remove solvent and then with successive washes of distilled water until a pH of 7.5 or below was reached. After a final Wash in tetrahydrofuran the cot ton was vacuum dried at 30 C. Degrees of Vinylation between 0.03 and 0.74 are obtained depending upon the length of time employed in the Vinylation reaction.

EXAMPLE 2 Vinylation of cotton cloth Unmercerized cotton printcloth (80-square) was cut into rectangular pieces measuring 4.75 inches by 3 feet for Vinylation in the l-liter autoclave or into pieces 9 inches by 6 feet for Vinylation in the 2-gallon autoclave. The catalyst was applied as follows:

The smaller pieces Weighing from 11.7 to 12.2 g. (0.072 to 0.075 unit moles) were placed in a large glass tube and soaked with 28.8 g. (23 cc.) of 6 N potassium hydroxide (0.14 moles). The cloth immediately soaks up the potassium hydroxide solution, and the tube which was closed with the rubber stopper was rolled in a horizontal position to complete the wetting and soaking. The tube was then allowed to stand for a period of l to 18 hours or more depending on the desired soaking time. The catalyst impregnated cotton weighing about 40 g. was then removed and squeezed through rubber pressure rollers set at a pressure setting of No. 4. After passing through the rolls, the cotton cloth weighed about 27 g.

The cloth was then dried by heating in a steam-heated laundry platen press at a temperature of about 235 F. for 30 seconds. In this process, the cloth was placed between several thicknesses of cotton printcloth. The upper plate of the laundry-press was steam heated and the lower plate was perforated to allow for the escape of moisture. The dried cloth weighed 18.4 g. It contained approximately 105 mole percent or 36 weight percent of potassium hydroxide and 16 to 21% of water as referred to the weight of the original cloth.

In the case of the larger pieces of cotton cloth which weighed between 44 and 46 g., 110 g. (0.53) moles of 6 N potassium hydroxide was applied by the same procedure as described above. After the soaking period, the cloth was passed through the pressure rolls and then weighed about 100 g. After drying in the steam press for 30 seconds, a catalyst impregnated cloth was obtained which weighed about 72 g. It contained approximately 36 weight percent of potassium hydroxide and 16 to 22% of residual water as referred to the weight of the original cloth.

After drying, the catalyst impregnated cloth was sewed fast around a cylindrical holder. Threads were passed through the edge of the cloth and looped through holes in the upper and lower rings of the cylindrical holder. The holder was then mounted on the stirring shaft in place of the stirrer in an autoclave. After charging the autoclave with sufiicient solvent to cover the cloth, the

autoclave was closed, sealed, and the Vinylation carried out. After the Vinylation was completed, the cloth was taken from the holder and washed, first with tetrahydrofuran and then with successive washes of distilled water until a pH of 7.5 was reached. The cloth was then squeezed through pressure rollers and air-dried for about 15 hours. It was then vacuum dried and weighed in order to determine product recovery.

The methods described above Were also used for the impregnation of cotton yarn or skeins of cotton yarn. Cotton yarn containing 2.6% volatiles was used in the experiments on the Vinylation of cotton yarn. After impregnation with catalyst and drying, the tied skeins of cotton yarn were placed in a stainless steel wire basket 2.75 inches in diameter and 1.5 inches high which Was attached to the stirring shaft of the autoclave. After charging the clave with sufficient solvent to cover the basket, it was closed, sealed, and the Vinylation carried out.

Vinylation experiments with SO-Square cotton printcloth demonstrated that good results could be obtained in toluene. D.S. values in the range of 0.20 were duplicated in both one-liter and two-gallon autoclave vinylations at 120 C. for a 6-hour reaction time. D.S. values of 0.48 and 0.74 were obtained in 12 and 24 hours, respectively, in toluene.

Cloth vinylated in toluene had good color and did not show loss of strength or puckering at the edges. Although the usual shrinkage was observed during treatment with the KOH catalyst, no further shrinkage occurred during the Vinylation.

Vinylation at 120 C. for 24 hours in di-n-butyl acetal of cotton broadcloth containing 100 mole percent KOH and 20% water (alkaline cloth dried in a rotating evaporator) yielded material with 19.5 mole percent vinyl ether or a D.S. of 0.20. The 6 N KOH impregnated cloth was allowed to soak for 20 hours before drying.

Vinylations performed in dibutyl acetal at 120 C. for a 6-hour period on cotton broadcloth pressure-roll padded with 6 N KOH to give a uniform 100 mole percent KOH pick-up followed by vacuum drying on a spindle to give cloth with 25 weight percent water (based on cotton) and 20 weight percent water resulted in products with respective D.S. values of 0.18 and 0.14 at very high product recoveries.

A temperature of 140 C. for Vinylation, gave a product recovery of only 63% with a D.S. vinyl ether of 0.16. Color formation in the direction of orange-yellow as well as fabric deterioration was noted.

The weight of dry vinylated cloth recovered was between and of the weight of the dry cloth used in Vinylation reaction runs of about 6 hours duration at C. and with the potassium hydroxide catalyst which conditions are our preferred conditions for vinylation.

We employed one or the other of the two methods described below to analyze our products.

Hydroxylamine method for vinyl ether plus acetaldehyde in cotton (simplified method) m1. (sample-blank) X N of NaOH Wt. of sampleX 1000 Determination of vinyl ether in cotton with iodine (improved method) mole/gram Accurately weigh a sample of vinylated cotton containmg approximately 0.001 mole of vinyl ether into a 9 16 oz. glass stoppered bottle. Add 50 ml. of methanol, 0.5 gram of sodium acetate and 50 ml. of 0.1 N iodine solution. Stopper the bottle and shake for hours on a mechanical shaker. Titrate the excess iodine with standard 0.1 N sodium thiosulfate to the disappearance of the iodine color. Determine a blank on 50 ml. of iodine solution in the same manner.

ml. (blank-sample) XN of Na S O wt. of sample 2000 Since the hydroxyla-mine method is more precise and appears to be the more accurate method at present, most of the samples analyzed with iodine were rechecked by this method. All analyses were performed with hydroxylamine unless otherwise noted.

Some formation of acetal cannot be ruled out by the above analyses, but it cannot be a very large proportion of the total substitution. This is especially true in those samples in which the iodine value comes up to the hydroxylamine value in a short time. The generally good agreement in results obtained by the iodine method and the hydroxylamine method indicate that little or no acetal is formed in the vinylation of cotton as described. The vinylation conditions used do not produce acetal when use for the vinylation of ethylene glycol, but in this case much acetal can be formed by carrying out the vinylation at 180 C.

Having thus described our invention, we claim:

1. A process for preparing chemically modified cotton cellulosic textile fibers etherified to a degree of substitution over the range of from 0.08 to 0.74 ether groups per anhydroglucose unit inclusive, which cotton cellulosic textile fibers are composed of cellulose molecules and etherified cellulose molecules arranged in the complex laminated structure characteristic of natural cotton cellulose textile fibers and which cotton cellulosic textile fibers are insoluble in cupraammonium hydroxide and insoluble in bis(ethylenediamine)cupric hydroxide and in which cotton cellulosic textile fibers the radicals that replace hydrogen atoms of cellulose hydroxy groups consist essentially exclusively of vinyl groups, which process comprises the following sequential operations:

(a) soaking the cotton cellulosic textile fibers at room temperature with an approximate 6 N aqueous solution of potassium hydroxide for a period of from 1 to 18 hours,

(b) reducing the water content of the soaked cotton cellulosic textile fibers with squeeze rolls to about 15 weight percent based on the weight of the cotton,

(c) vinylating the cotton cellulosic textile fibers from mole/ gram vinyl ether:

step (b) with acetylene at a temperature of about C. and a gauge pressure of about 120 pounds per square inch, said fibers being suspended in an acetylene solvent selected from the group consisting of di-n-butyl acetal, di-iso-butyl acetal, tetraethylene glycol dimethyl ether and toluene for a period of time sufficient to produce a chemically modified cotton cellulosic textile material etherified to the desired degree of substitution selected over the range of from 0.08 to 0.74 vinyl ether groups per anhydroglucose unit inclusive, and (d) separating the vinylated cotton cellulosic textile fibers from the acetylene solvent by washing with tetrahydrofuran to recover solvent-free chemically modified cotton cellulosic textile fibers, washing the recovered acetylene solvent-free fibers with distilled water to a pH not exceeding 7.5, then washing with tetrahydrofuran, and vacuum drying at 30 C. to remove the tetrahydrofuran. 2. The product produced by the process of claim 1. 3. A smooth drying crosslinked cotton textile fabric with wash-wear properties prepared by the process of soaking cotton cellulosic textile fabric, which fabric has been vinylated according to the process of claim 1 to a degree of substitution of at least 0.20 vinyl ether groups per anhydroglucose unit with an approximately 2.0% by weight aqueous solution of an acid type polymerization catalyst and subsequently heat curing the soaked fabric at a temperature of about 300 F. for a period suflicient to essentially complete the reaction.

References Cited FOREIGN PATENTS 1/1961 Australia.

OTHER REFERENCES GEORGE F. LESMES, Primary Examiner J. R. MILLER, Assistant Examiner US. Cl. X.R. 

